Pvc manifold

ABSTRACT

Manifold for dividing molten PVC stream into a plurality of branch streams wherein the trunk passageway is divided into a plurality of diverging branch passageways none of which makes an angle of less than 110* with the trunk passageway and any adjacent two of which converge with one another at a sharp stream splitting wall intersection of 140* or less. In the preferred form of the present invention four parallel one-fourth to onehalf inch secondary branch passageways are provided by dividing a first trunk passageway into two branch passageways symmetrical with respect to the trunk passageway converging with one another in an angle of about 140*, each of which is subsequently divided into secondary branches one of which makes an angle of 110* with the first branch and the other of which is coaxial with the first branch for a short distance and then is angled to parallel the other secondary branch.

United States Patent Wheaton, III et al.

[is] 3,704,723 1 Dec.5,1972

[54] PVC MANIFOLD [72] Inventors: Theodore C. Wheaton, 111, Ocean City;Daniel J. Mikus, Vineland, both of NJ.

[73] Assignee: Wheaton Industries, Millville, NJ.

[22] Filed: Aug. 16, 1971 211 App]. No.: 175,118

[52] US. Cl ..137/34l, 137/561 A, 259/4 [51] Int. Cl. ..B01f 15/02 [581Field of Search ....259/4, 18; 239/142, 143, 402;

Fleming ..137/608 Kautz ..259/4 Primary Examiner-Robert W. JenkinsAttorney-Henry N. Paul, Jr. et al.

[57] ABSTRACT Manifold for dividing molten PVC stream into a pinralityof branch streams wherein the trunk passageway is divided into aplurality of diverging branch passageways none of which makes an angleof less than 1 10 with the trunk passageway and any adjacent two ofwhich converge with one another at a sharp stream splitting wallintersection of 140 or less. In the preferred form of the presentinvention four parallel one-fourth to one-half inch secondary branchpassageways are provided by dividing a first trunk passageway into twobranch passageways symmetrical with respect to the trunk passagewayconverging with one another in an angle of about 140, each of which issubsequently divided into secondary branches one of which makes an angleof 1 10 with the first branch and the other of which is coaxial with thefirst branch for a short distance and then is angled to parallel theother secondary branch.

6 Claims, 3 Drawing Figures PATENTED DEB 51972 INVENTORS.

heoton HI us dore CW 'el J. Mik

Theo BY DGHI ATTORNEYS.

PVC MANIFOLD This invention relates to a manifold for dividing a streamof molten polyvinylchloride into a plurality of such streams fordelivery to a corresponding plurality of molds therefor. Moreparticularly, it relates to such a manifold intended to maintain themolten condition of the PVC while preventing degradation thereof anddelivering the same while in a condition of near optimum moldability.

Numerous manifolds have been developed for dividing a plastic stream,thereby to feed the plastic material into one of a plurality of moldstherefor. While a great deal of expertise has been developed inoptimizing the dimensions and geometry of such manifolds for varioustypes of plastics and various types of molding apparatus, there hasheretofore been no known manifold capable of dividing a stream of moltenpolyvinylchloride and, while preventing degradation thereof, dividingand delivering the PVC to some form of plurality of molds for moldingapparatus. Generally the problem is that PVC is either degraded ordelivered in a form unsuitable for molding.

The general object of this invention is to provide a manifold which willeffectively divide a molten PVC stream and deliver the PVC into aplurality of branches with practically no degradation thereof and in acondition suitable not only for molding but for the injection molding ofparisons which are thereafter blowable into hollow articles.

Briefly, these objects and others which will become apparent in thecourse of the subsequent discussion, are met by a manifold in whichsmooth walls are maintained throughout the trunk and branch passagewaysthereof. The relationship between the trunk and branch passageways issuch that no branch passageway makes an angle of less than 110 with thetrunk passageway and any two adjacent converging branch passageways forma closed angle between them of no more than l4(). Moreover theintersecting walls of adjacent convergent branches present a sharp,non-rounded line of intersection to split the molten PVC issuing fromthe trunk passageways. Each such branch passageway may in turn serve asa trunk line which is similarly split. The temperature of the passagewayis generally maintained in the range of 320F to 380F for most types ofproduction and the passageways are generally circular in cross-sectionwith diameters in the range of onequarter to one-half inch.

In the preferred form of the present invention, a single trunkpassageway is divided into two branches converging symmetrically aboutthe axis of the trunk with a converging angle of about I40". Theseconverging branches are in turn separated in four secondary branches,each of the primary branches being divided into one secondary branchwhich is coaxial with the first branch and a second secondary branchwhich forms an angle of 1 with the first branch. The coaxial secondarybranch thereafter makes a 110 turn so that four secondary branchesresult which are parallel to one another and the axis of the incomingtrunk passageway. Maximum diverging angles are used in this preferredembodiment so as to minimize the residence time of PVC in the manifold.In the preferred embodiment, wherein there is also included means fordelivering PVC to the trunk passageway at a temperature of 320F to 380F,a pressure of 6,000 to 9,000 PSI and a rate of 3 to 6 grams/sec, all ofthe passageways are circular. The diameters of the trunk and primary andsecondary branches, respectively, are all on the order of one-half inch.

This invention may be better understood by reference to the followingdetailed discussion taken in conjunction with the appended claims andthe attached drawings, in which:

FIG. I is a front view of the preferred embodiment of the PVC manifoldof the present invention;

FIG. 2 is a plan view in section of the manifold shown in FIG. *1; and

FIG. 3 is a detailed sectional view of a part of the manifold shown inFIGS. 1 and 2.

Referring more specifically to FIG. I,there is shown outlet nozzles 2retained by manifold face plates 4 and face plate bolts 6 on manifoldbody 8.

As shown in the sectional view of FIG. 2, manifold body 8 and manifoldinlet nozzle receiving member 10 together define trunk passageway 12,primary branch passageways 14, diverging from trunk passageway 12 atangles of 1 10, and secondary branch passageways 16. It will be notedthat in this the, preferred embodiment of the present invention, eachpair of secondary branch passageways 16 includes one secondary branchwhich diverges from primary branch passageway 14 at an angle of and asecond secondary branch which continues coaxially with primary branchpassageway I4 and then turns 110 to become parallel with the othersecondary branch passageway of the pair. In this way four parallelsecondary branch passageways result all terminating in nozzles 2.

Inlet nozzle receiving member 10 is retained in manifold body 8 byretainer member 18 and, as seen in FIG. 3, the passageways of inletnozzle receiving member 10 are maintained in alignment with those ofmanifold body 8 by tapered shaft member 20 seated in openings 22 and 24therefor in manifold body 8 and inlet nozzle receiving member 10.

For various manufacturing and maintenance reasons, inlet nozzlereceiving member 10 preferably comprises a threaded removable segment10a in which is incorporated trunk passageway 12 and inlet nozzle seat26.

Removable portion 10a of inlet nozzle receiving member 10 and taperedshaft member 20, along with openings 22 and 24 therefor, may be betterseen in the detailed sectional view of FIG. 3, in which is also shownradiant heating members 28 located in openings 30 therefor in manifoldbody 8.

Generally, passageways 12, 14 and 16 are circular in cross-section, withdiameters on the order of onequarter to one-half inch, and have smoothinterior sidewalls, free of protuberances. The lines of intersection 32and 36 of diverging branch passageway walls are preferably sharp andunrounded. In the preferred form of the manifold shown in FIGS. l-3, thediameters of primary branch passageways l4 and secondary branchpassageways 16 are all approximately one half inch. In operation, moltenPVC is supplied to inlet nozzle receiving means at a temperature in therange of 320F to 380F, a pressure of 6,000-9,000 PSI and a flow rate of3 to grams per section. Heating means, such as radiant heaters 28, areused to maintain the manifold at a temperature of 300F to 350F. Fourshots, of 12 to 50 grams each, of injection moldable form angles of 180and 1 respectively with the axis of primary branch passageways 12. Inthis, the preferred form of the present invention, one of the secondarybranch passageways 16 on each side of the manifold is coaxial with itsrespective primary branch passageway 12 and continues in the same axialdirection as that of primary branch passageway 12, thereafter making a110 bend so that all four secondary branch passageways 16 exit themanifold of the present invention inparallel equally spaced relationshipfor convenientdelivery of molten PVC to multiple mold cavities.

Apart from the smoothness of the interior sidewalls of the passagewaysin the manifold of the present invention, and absence of protuberancestherein, it is extremely important that passageway wall intersections ofconverging branch passageways or, conversely considered, the divergingpaths of a PVC stream being split, intersect with a sharp, non-roundedangular apex splitting the molten PVC stream. In the manifold shown inFIG. 2, such sharp, non-rounded stream splitting intersecting wallsurfaces are seen at passageway wall intersections 32 and 36.

Obviously, the dimensions of the passageways in the manifold of thepresent invention will depend on the flow rate of material and othervariables. Trunk passageways may be, although they need not be, oflarger diameter than subsequent branch passageways. Generally, however,for a machine in which the molten PVC is delivered to the manifold at apressure in the range of 6,000 to 9,000 PS1 and at a rate in the rangeof 3 to 6 grams/sec as is the case in the apparatus in which thepreferred embodiment of this invention is used, the various trunk andbranch passageways are all in the range of one-quarter to one-half inchin diameter.

Utilizing the manifold of the present invention, PVC bottles have beeninjection blow molded on otherwise conventional injection blow moldingequipment. This is in sharp contrast to prior experience which hasindicated that any manifold in which a molded PVC stream is dividedcauses either degradation of the PVC or a change in the condition of thePVC rendering molding, and particularly injection blow molding, thereofdifficult if not impossible. Passageway configurations, angulardiversions, the geometry of stream cal PVC manifold is thought to be theessence of the present invention.

It should of course be understood that while this invention has beendescribed with respect to particular embodiments thereof, it is notlimited thereto and in fact the appended claims are intended to coverall other embodiments and modifications which will be apparent to thoseskilled in the art and which are within the true spirit and scope of thepresent invention.

We claim: v

l. Manifold for dividing a molten polyvinyl chloride stream in a trunkpassageway into a plurality of such streams in branch passageways, saidmanifold defining said trunk passage-way and said plurality of branchpassageways, means for maintaining all of said passageways at 300 to350F, all of the walls of all said passageways being smooth, any twoadjacent branch passageways converging at an enclosed angle of no morethan 140 with a sharp, non-rounded line of intersection therebetween,and an enclosed angle between any, of said branch passageways and saidtrunk passageway of more than 1 10.

2. Manifold, as recited in claim 1, wherein said branch passageways arein turn divided into secondary branch passageways, said secondary branchpassageways also having smooth walls and means for maintaining thetemperature thereof in the range of 300 to 350F, said secondary branchpassageways forming no angle with said first branch passageway of lessthan any adjacent two of said secondary branch passageways converging atan angle of no more than with a sharp line of intersection therebetween.

3. Manifold, as recited in claim 2, wherein all of said passageways arecircular in cross-section, wherein the diameter of said trunk passagewayis one-quarter to one-half inches, the diameter of said branchpassageways is one-quarter to one-half inches, and the diameter of saidsecondary, branch passageways is onequarter to one-half inches, andwherein said trunk passageway is divided symmetrically into two branchpassageways converging with an enclosed angle therebetween of 140, eachof said branch passageways in turn being divided into two secondarybranch passageways, one of said secondary branches being coaxial withsaid branch, thereafter making an 110 bend, the other of said secondarybranches intersecting said branch at 1 10, all of said intersections andbends being such as to result in four secondary branch passageways allparallel to the axis of the trunk passageway.

4. Manifold, as recited in claim 3, wherein the diameters of all of saidpassageways is on the order of one half inch.

5. Manifold, as recited in claim 1, combined with a means for supplyingpolyvinyl chloride at a temperature of 320 to 380F, a pressure of 6,000to 9,000 PS1, and a rate of 3 to 6 grams/second, said passageways beingcircular in cross-section and having a diameter of one-quarter toone-half inch diameter.

6. Manifold, as recited in claim 1, wherein said trunk passageway iscircular in cross-section, has a diameter of one-quarter to one-halfinch and is divided into two branch passageways, each circular incross-section with a diameten of one-quarter to one-half inches, saidbranch passageways converging at an angle of 140 and each intersectingsaid trunk passageway at 1 10.

lm l06009 0166

1. Manifold for dividing a molten polyvinyl chloride stream in a trunkpassageway into a plurality of such streams in branch passageways, saidmanifold defining said trunk passage-way and said plurality of branchpassageways, means for maintaining all of said passageways at 300* to350*F, all of the walls of all said passageways being smooth, any twoadjacent branch passageways converging at an enclosed angle of no morethan 140* with a sharp, non-rounded line of intersection therebetween,and an enclosed angle between any of said branch passageways and saidtrunk passageway of more than 110*.
 2. Manifold, as recited in claim 1,wherein said branch passageways are in turn divided into secondarybranch passageways, said secondary branch passageways also having smoothwalls and means for maintaining the temperature thereof in the range of300* to 350*F, said secondary branch passageways forming no angle withsaid first branch passageway of less than 110*, any adjacent two of saidsecondary branch passageways converging at an angle of no more than 140*with a sharp line of intersection therebetween.
 3. Manifold, as recitedin claim 2, wherein all of said passageways are circular incross-section, wherein the diameter of said trunk passageway isone-quarter to one-half inches, the diameter of said branch passagewaysis one-quarter to one-half inches, and the diameter of said secondarybranch passageways is one-quarter to one-half inches, and wherein saidtrunk passageway is divided symmetrically into two branch passagewaysconverging with an enclosed angle therebetween of 140*, each of saidbranch passageways in turn being divided into two secondary branchpassageways, one of said secondary branches being coaxial with saidbranch, thereafter making an 110* bend, the other of said secondarybranches intersecting said branch at 110*, all of said intersections andbends being such as to result in four secondary branch passageways allparallel to the axis of the trunk passageway.
 4. Manifold, as recited inclaim 3, wherein the diameters of all of said passageways is on theorder of one half inch.
 5. Manifold, as recited in claim 1, combinedwith a means for supplying polyvinyl chloride at a temperature of 320*to 380*F, a pressure of 6,000 to 9,000 PSI, and a rate of 3 to 6grams/second, said passageways being circular in cross-section andhaving a diameter of one-quarter to one-half inch diameter.
 6. Manifold,as recited in claim 1, wherein said trunk passageway is circular incross-section, has a diameter of one-quarter to one-half inch and isdivided into two branch passageways, each circular in cross-section witha diameter of one-quarter to one-half inches, said branch passagewaysconverging at an angle of 140* and each intersecting said trunkpassageway at 110*.